Railway signaling apparatus



1,628,290 May 10 1927' H. A. WALLACE RAILWAY SIGNALING APPARATUS Filed Oct. 9, 1926 INVENTOR W Q AALOV KL 2 u Patented May 10, 1927.

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HERBERT A. WALLACE, OLE EDG EVJ'OOD BOROUGH", PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SVVISSVALE, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA.

RAILWAY SIGNALING APPA'IRATUS.

Application filed October 9, 1926. Serial No. MOAEO.

My invention relates to railway signaling apparatus and particularly to apparatus of the type comprising railway signals located in the trackway for governing the passage of railway vehicles. More particularly my present invention relates to apparatus for controlling railway signals of the type usually designated as slotted electric signals,

- that is, signals of the type comprising an operating mechanism made .up of a driving motor tor moving the signal from its normal or de-energized position to a second position in which latter position the signal is held by a'slot mechanism, the driving motor being disconnected when the signal reaches its operated position.

I will describe one form of railway signaling apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view illustrating one form of railway signaling apparatus embodying my invention. 1

Referring .to the drawing, the reference characters 1 and 1 designate the track rails of a stretch of railway track over which traffic normally moves in the direction indicated by the arrow. These track rails are divided by means of insulated joints 2 into a plurality of successive track sections, only one of whiclnA-B, is shown complete in the drawing. Traffic over the stretch of trackshown in the "drawing is governed by trackway signals each designated by .the reference character S with an exponent corresponding to the location, and in the form here shown each signal is of the three-position semaphore type capable of indicating proceed, caution or stop. Eachsignal is ,located adjacent the entrance end of the corresponding section. It should be understood, of course, that this particular arrangement and construction of the signals S is not essential to my invention. For controlling the signal 8", section AB is provided with a polarized direct current track relay R connectedacross the rails adjacent the entrance end of the sect-ion. Track circuit current is supplied to the rails of section ii- B from a battery K connected across the rails adjacent the exit end of the section. The polarity of the track circuit current supplied to the rails of the section A-B by the battery K is controlled bya pole-changer P operatively connected with signal S and arranged to occupy one positionwhen the signal indicates caution or proceed and to occupy the other position when the signal indicates stop.

It should be pointed out that while I have shown only section AB provided with a track :circuit including a track battery A, a pole-changer P, and a track relay R, each of the remaining sections are provided withsimilar apparatus.

The operating mechanism of signal S is at times supplied withenergy from a suitable source such as a battery D. hen signal S indicates stop, the relative polarity of the current supplied to relay R is such that the polar contact 3 of the relay is open, but the front contacts 21 and 22 are closed. Under these conditions, current flows from battery D, over wire 4, front contact 21 of relay R, wires 5 and 6, operating mechanism or" signal S wires 7 and 8, front contact 22 of relay R, and wire 9, back to battery D. When this circuit is closed, the signal S displays a caution indication. WVhen signal S indicates proceed or caution, however, pole-changer P is reversed and the polarity of the .current supplied to relay R is then such that relay R closes its polar contact 3. Under these conditions the caution circuit just traced is closed and in addition a proceed circuit is closed frombattery D,through wire 4;, .front contact 2l of relay R, wires 5 and 10, polar contact 3 of relay R, wire 11, operating mechanism of signal S wires 7 and 8. front contact 22 of relay R, and wire 9 back to battery D. When this circuit is closed, signal S displays a proceed indication. WVhen section AB is occupied by a train, relay R becomes de-energized, interrupting both the proceed circuit and the caution circuit for signal S and causing that signal to indicate stop.

Polarized direct current relays of the type commonly used in railway signaling systems are so constructed that when the polarity of the current supplied to the relay is reversed,

the relay first opens its front cont-acts, next reverses the polarized armature, and finally recloses the front contacts. With relays constructed in this manner it-will be apparent that should signal S be at caution or proceed and should pole-changer P be relUO versed. the neutral ,lrout contacts oi relay livvould be open tor a briel inter *al of time during the reversal in the direction of eneraization oi relay it. During; this brief inter- "al of time, the circuit or circuits forthe operating mechanism of signal ti would be interrupted. and it might happen that this interval of time could be long: enough to per wit the slot mechanism of the signal to release and allow the signal to return to the stop indication.

I therefore provide a translermer Thaw inn a primary 19 and a secondary 20. The primary 1.9 of this transformer is provided ivith a circuit which may be traced from battery I), through wire 19.. a circuit controller J operated by signal Si", wire 13, primary 19 of transformer '1, wire I l, baclt contact 22 of relay ll, and wire 9 back to battery D. The circuit controller J is arranged to be closed only when signal gt indicaites caution or proceed. and the primary circuit tor transformer T is therefore closed only when relay 1" becomes tlQ0llGll'1Zt1(l with signal 53 at caution or proceed. The secondary of transformer T is provided with a. circuit which passes from the righthand terminal of this secondary. through wire 15. back contact 31 of relay It, to Wire 5 and thence through Wire 6 (or through wire 10, polar contact and wire 11) to the operating mechanism of signal 8*, returnins: throuuh Wires 7 and 16 to the left-hand tei'ininal 6r secondary 20 of transformer T.

To explain the operation of the apparatus I will assume that the relay R is energized in the reverse direction so that polar contact 3 is open; signal S then indicates caution and circuit controller J is closed. I will now further assume that relay R opens its front contact and closes its back contacts for a brief interval of time. For example, this could happen if pole-changer 1 became reversed as by the movement of signal S from step to caution. The closinfo, of back contact 522 of relay R completes the. circuit for primary 19 of transformer 'l. A stage of current is therefore supplied to primary 19 from battery I). As a result ot the increasing current in the primary 19 an eleetromotive force is induced in second ary Qt) which supplies current to the operating: mechanism of the signal over back contact 21 of relay R in the same direction as the current which is normally supplied to the operating mechanism tron; battery l). (it course the current supplied to the o 'ieratiupg mechanism. oi the signal by the seeoi'ulary oi. transformer l isonly a surge. and this current ceases as soon as the current in the primary of transformer has attained a steady value, but I have discovered that in actual practice this surge of current is sutlicient to maintain the slot mechanism in its energized condition and to prevent the release o I the signal during hriei interruptions of the operating cir cuit tor the signal resulting from te1nporary opening; oi the front contacts of relay R.

In order to prevent arcing at back contact I connect a rectifier 17 of any suitable type in parallel with the primary 19 ot translm'iner T. The rectifier is so disposed as to other its higher res tance to current supplied to the primary from battery D. ll lien back contact 252 is opened, however, to interriupt the circuittor pri mary 1.9, the energy stored in the magnetic lield surrolunling the primary tends to force a current through the rectifier 17 in its lower resistance direction. this connection then, the energy of the magnetic field is dissipated through the rectifier '17 and the formation of a destructive arc is prevented at back contact 22. For a similar purpose a second rectifier 18 is connected in. parallel with the secondary 20 of transformer T to prevent arcing at back contact 21 of relay R.

Although I have herein shown and described only one form of railway signaling apparatus embodying my invention, it is understood that various changes and modifications may be made therein Within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

1. In combination with a railway signal having the usual operating mechanism, a circuit for said mechanism, means for at times interrupting such circuit for a brief interval, and means for supplying a surge of energy to the mechanism during such interval.

2. In combination with a railway signal having; the usual operating mechanism, a relay, means for at times energizing the relay, means effective when the relay is energized to supply energy continuously to the operating mechanism of the signal, and means effective when the relay becomes deenergrircei'l to supply the mechanism with a surge of energy.

l n combimttion, a railway signal, a relay controlled in accordance with tratlio conditions, a. circuit for the O[')01' Ll lI1g mechanism ot the signal including: a source of energy and a. front, contact of the relay, a transformer having its primary connected with the source over a. back contact of the relay, and a second circuit for the operatingr mechanism of the signal including the secondary of the transformer and a back contact of the relay.

l. In combination, a railway signal, a relay controlled in accordance with tratlic conditions, a circuit for the operating mecha- As a result of Oil ill)

till) i the operating mechanism of the signal innism of the relay including a source of energy and a front contact of the relay, a transformer having its primary connected with the source overa back contact of the relay, a second circuit for the operating mechanism of the signal including the secondary of the transformer and a back contact of the relay, and a rectifier connected in parallel with one winding of the transformer to prevent arcing at the back contacts of the relay.

5. In combination with a railway signal, a relay, a circuit for the operating mechanism of the signal including a front contact of the relay, and means effective when the relay becomes de-energized with the signal in its operated position to supply a surge of energy to said operating mechanism.

6. The combination, with a railway signal, a polarized relay, a caution circuit for eluding a front contact of the relay and a source of direct current, and a proceed circuit for such mechanism including a front contact and a polar contact of the relay and said source, of a transformer having its primary connected with the source through a back contact of the relay, and means including a back contact of the relay for supplying energy from the secondary of the transformer to the operating mechanism of the signal.

7. In combination, a railway signal, a

first circuit including the signal and at times including a source of energy, a sec 0nd circuit including a source of energy, and means for transferring energy from the second circuit to the first circuit for a brief interval when the source of energy is disconnected from the first circuit.

In testimony whereof I affix my signature HERBERT A. WVALLACE. 

